Window construction



Feb. 5, 1952 D, ALPERT 2,584,653

WINDOW CONSTRUCTION Filed Nov. 28, 1945 fig. 2.

INVENTOR .Dan/e/ 1940er?.

ATTORNE Patented Feb. 5, 1952 aan;

Lasa-1,65, `Wip oWfoNsfrtUefrio Daniel Alpert,Fiati-Pittsburgh;'j@SSghOI.if Y Westinghouse Electric Corporation,EastPitts- .burgh, Pa., a corporationgf lennsylyania ApplicationNovember Z, 1 9'4 Serial No. 63l7, 399:` v

. z claims. fici.

f I'Ihis i invention relates to a metal-supported glass window andto themethod of vmaking such a window; r Y

. rIn `manufacturing various products, it is often necessary to, providea vacuum-tight glasswindow acrossan opening in a metal body having acoeiientxof. expansienconsderably higher than that of the glass. In thefield of ultra-highnequeny electromagnetic energy,.for example, itisdesirablelto have sucha window across an openingin the body of a vcavityresonator, as lshown in my .copendingapplicatiom Serial No. 480,991,filed March 29, 1 943 now Patent Number 2,525,456.- The body-of thecavity resonator, being formed necessarily of a highly conductive`material such' i* asfcopper orbrass, hasa high coefdcient of. ex-vpansion. As illustrated in my copending application, vthe window forAsuch .a body is formed of ayiiat `xnet'allic jplate having an opening4therein' lled with glassof-substantially the samethickz nessastheplatewith a glass-toV-metalaseglgat the edges o f theopening. vThefmetallicplateis formed o f an .alloyhaving substantially the saine coeiiicientof expansion as the glass and is rigidly i secured with a vacuum-tightjoint to the body."

, The prior arrangementfjust described `isquite satisfactory undermany'conditions even greater efficiency is desired in the'large scalemanufacture of windows than is provided by known methods of producingwindows'of1- this` type. When high-frequency heating is employed inmaking the glass-to-metal Aseal in such af window, the glass of thewindow is invariably. asymmetrialand the sides thereof are not 1substantially flat. -Y Such a glass window causesfa diierence inthe amountof electromagnetic energyv-passing throughfdifferent parts of thewindow, increases the mechanical 4 di'iculties'V in' mounting thewindow, and renders'the windowl more susceptible to failure understress, More? glasswindowl.

a new and improvedmetalysupported glass window which may be readily andefciently manufactured inv large quantities.

'fAfurther object of my invention is to provide a'"nove1metal-supportedglass window adapted to,cbe-rigid1y mounted'on a bodyhaving a coefficient of expansion substantially higher. than that-softhe glass. f f

l'sStillanother object of my invention is to providea novel method offorming a metal-supported glass window.

The Afeatures-of my invention which I consider novel areset forth withparticularity in the accompanying claims. Theinvention itself, however;together: vwith additional objects and advantages thereof maybe betterunderstood from the following description of a specific embodiment whenread Yin'connection with the accompanying drawing, in which:v 1

1. Figure l is a plan view of a metal-supported glass window embodyingmy invention, as mounted: on a body` having a high coeiiicient ofexpansion;

-.Fig. 2'is an enlarged cross-sectional lView taken along linel'I--TIyof Fig. 1; and

`:liig.i3 .is a partial view in section of the window of. my inventionYillustrating the position of the glassbeioreand after sealing to themetal support. 1 i-lAs shown in the drawings, a Window is provided foruse with a metal body 5 having a high coeiiicient of expansion. By avhigh Acoefficient of` expansionI mean one greater than that of asuitable'glass so as to preclude a satisfactory glass-to-metal sealbetween the glass and body for the purposes desired. iThe body 5 has anopening 'l' therein and may also have an annular recess 9 providedaboutthe opening l on the outer side'of the body in-which recess the windowis mounted across the opening.

The'window comprises a relatively thin metaliic'frame 'Il 'having acentral opening therein. The plate is formed to have the opening boundedby a surface I3 which inclines away from the center lineof the openingbyanv angle of the order of 70 degrees. A at plate-like glass mem ber l5is mounted across the opening in the frame H and has its edgesconfor-ming with; and sealedtdthe inclined surface I3. The frame Il is,provided.; with deep annular corrugations be.-

tween its outer periphery and the glass-to-metal seal, the corrugationshaving a depth up to ten times the thickness of the metal of the framewhich is relatively thin so that the frame is exible between the sealand its outer periphery. The frame II is rigidly secured to the body 5by soldering thereto all around the outer periphery of the frame. With avacuum-tight glass-tometal seal and with a vacuum-tight joint betweenthe frame II and the body.5, a vacuum may be established on the lowerside of the body as in Fig. 2 which would tend to` draw the window downagainst the/bottom of the recess 9.

The frame II is preferably formed of an alloy comprised essentially ofnickel, cobalt and ironr a preferred composition having approximately23% to 34% nickel, 5% to 25% cobaltwith substantially all of theremainder being iron. With Athis alloy, a borosilicate glass whichisnsuitable for sealing with the alloy and having substanf tially thesame coefficient of expansion as the alloy is employed. Seals between analloy com-f prised essentially of nickel, cobalt and iron and aborosilicate glass as may be here employed are described in detail inthe Scott Patent No. 2;2"17,42f1-of-Octolier,y 1940;-rv .l

InA manufacturing then'window, a sheet of alloy is first stamped `andpunched to form the frame IIA'haying theopening bounded by the inclinedsurface with the corrugations between the inclined vsurfacerand theouter periphery of the frame'. Then-the frame-is supported withthe Ycenter line o f the opening therein -substantially Vertical and theinclined surface facing'upvvard. AM substantially flatplate-like glassmember is placed on top of the frame acrossthe opening therein asillustrated by the dotted aline member I5'l of Fig. 3; Theiglass memberI5A is substantially uniform in thickness with its edges at right anglesto the sides thereof, the .glass having the same general configurationbut beinglarger'than the opening in the frame whereby the corners formedby theedgesand lower side of the glass member I5 rest on the inclinedsurface S3 with thelower side abovethe lower extremity of theinclinedrsurface I3 by a vertical distance substantially -no less thanone-half vthe thickness of the glass member. Thereafter the frame may beheated by any suitable method, such as by highfrequency heating- As theframe-is heated, the portion of the glass engaging and adjacent to theframe Vbegins to melt and the'glass member slides downward By the timethe glass member reaches the horizontal position shown by the solidlinemember I5 in Fig. 3, the edges of the glass rncnber. conformwith`and engages the inclined surfacerof theframe as shown. At this time,heatingv offthe' metallic plate is stopped andthe glass-,to-metal sealat the inclined surface is completed. It is to be noted that the angleofthe incline surface ISof the frame is of importance in determiningthel cross-sectional configuration of 'the glass member I5-afterv theseal is made. I have discovered that using-,the alloy and the glassmentioned `with the inclined surface I3 at an angleof-the order of 70degrees to the verticali, the forceoffgravty, thesurface-tension betweenthe metal and-theglass, and such other factors as may affect the actionof the glass, 'combine to enableproduction-of the glassto-metalseal asdescribed with each side of the glass member substantially flat over itsentire surface at the compl-etion cfu-the seal. This permits uniformpassage-of.electromagnetic-energy through the glass and makes itpossible to rlt the window accurately with other machined metal parts.In addition, the area of the glass-to-metal seal is very large withrespect to the thickness of the glass member which adds considerably tothe strength of the seal and Window.

Along with the added strength of the Window, the provision of a framewhich is flexible between the glass and the points at which the frame issecured to the body results in greatly increased protection againstfailure of the Window under temperature change. By this arrangement,relative movement ofthe body 5 and the glass member l5 caused bytemperature changes is absorbed in the flexible frame I I.

It is to be noted particularly that the frame is exiblegradially fromthe center of the opening therein.

lfinit ttin'g' of the body to other rigid parts of a system, andexpansion and contraction of the body radially with-respect to theWindow is taken up in the flexible frame. I have found that in suchwindow of the approximate proportions shown in Fig. 2, in which theframe has an outer diameter of the order of inch and the opening thereinhasta diameter of the order of inch, the outer diameter of the frame maybe changed by as muchas iOlinch without damaging the seal-or glass WhileI have illustrated the frame as havinga circular outline and withacircular` opening, other shapes may, of course; be used.i

It isf'also to be noted that the frame for the Window may beeasilyformed in a punching operation -and the use `of the inclinedsurface elimin 'ates the need'for any rounding or polishing of theVframe in 'p're'paration for the sealing operation; Moreover,high-frequency heating may be efficiently/used `in making the seal sothat the entire window" may be readily and inexpensively manufactured.`

,While I have shown-and described a preferred embodiment of myinvention, I am Aaware that many modifications-thereof `may be madeWithout departing from the spirit of the invention. It is not myintention, therefore, to limit the Vinvention tothe specific arrangementdisclosed.

I claim as myfinventi'on':

1. A metal supported glasswindow for use With a' body' cfa` materialhaving a high coeihci-ent'of expansion, comprising a frame of an alloycomprised essentially of nickel, cobalt and iron, said frame having anopening therethrough bounded-on onerside of the frame by a boundarysurface inclined away from the center line'of said opening at anV angleof they order of 70 degrees, and-a'- 'glass' plate member extendingacross said opening substantially perpendicular to said centerline-withthe peripheral edges thereof conforming with ,and sealed to KAsaidboundary surface, said glass `member* being of a borosilicate glas'shaving substantially the same coefficient of expansion as said alloywhich is lower than ,.thatfof, said body, said frame being adapted to 5,providing a boundary surface about said opening on one side of the framewhich is inclined away from the center line of said opening at an angleof the order of 70 degrees and also providing corrugations surroundingsaid boundary surface whereby said frame isflexible in the region ofsaid corrugations, and a borosilicate glass plate extending across saidopening perpendicular to said center line with the peripheral edgesthereof conforming With'and sealed to said boundary surface, said glasshaving substantially the same coeicient of expansion as said alloy.

DANIEL ALPERT.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 1,614,156 Schmidt Jan. 11, 19272,050,576 Kronquest Aug. 11, 1936 2,075,477 Smith Mar. 30, 19372,219,573 Fraenckel Oct. 29, 1940 2,259,751 Kelley, Jr Oct. 21, 19412,296,307 Power Sept. 22, 1942 2,318,435 Stupakoi et al. May 4, 19432,419,049 Alpert Apr. 15, 1947

